含VSC-HVDC并网风电场的电力系统最优潮流计算

Optimal power flow of wind farm grid-connected system based on VSC-HVDC

由于风电场出力的实际值通常在预测值附近随机波动,所以在潮流计算时还应考虑风电场出力的随机性。针对风电场通过VSC-HVDC并网的情形,为了使电网既能安全运行,又能实现经济调度,提出了一种基于场景分析的最优潮流计算模型。模型以火电机组的总成本最小为目标函数,并考虑火电机组在预测场景和误差场景有功出力的调节范围约束,采用内点法进行求解。算例结果表明,引入误差场景后,虽然火电机组的总成本增加了,但是风电场出力的随机性对火电机组快速调节出力能力的要求得到了满足,从而保障了电网的安全运行。

The actual value of wind power output varies randomly around the predicted value, thus, the randomness of wind power output should be considered in the power flow calculation. This paper proposes an optimal power flow calculation model based on scenario analysis of the wind farm connected to AC grid by VSC-HVDC, which can achieve secure operations and economic dispatch. The minimum total cost of thermal power plants is taken as the objective function of the model, and the adjusting range of active power output of thermal power plants under the forecasted wind power scenario and sampling scenarios is considered as constraints. Afterwards, the model is solved by utilizing interior point method. The calculation results show that, although the total cost of thermal power plants is increased after introducing sampling scenarios, the requirement of the capability of thermal power plants that can quickly adjust the randomness of wind power output is satisfied, thereby, the safety of grid operation is guaranteed.